Analysis of medicinal cannabis

Doctors have been allowed to prescribe medicinal cannabis for ten years now. But how often and to which patients it is prescribed was hitherto unclear. Together with Arno Hazekamp, his colleague from Leiden, Utrecht pharmacoepidemiologist Rob Heerdink decided to analyse the prescription of medicinal cannabis. "The distribution has been stable for ten years, so obviously patients are satisfied."

In 2001, Els Borst, then Minister of Health, Welfare and Sport, set up the Office of Medicinal Cannabis, which enabled the government to produce and distribute medicinal cannabis according to international legislation. Two years later, cannabis was legally grown and prescribed for the first time. Medicinal cannabis has been prescribed for ten years now, but insight into the distribution and consumption is still somewhat limited, according to Rob Heerdink, pharmacoepidemiologist at Utrecht University. Therefore, Heerdink decided to start a retrospective study into the distribution and consumption of medicinal cannabis together with pharmaceutical researcher Arno Hazekamp of Leiden University.

Six to seven portions

"Patients usually use a vaporiser or they make tea of the medicinal cannabis", explains Heerdink. "They do not smoke it, because that is bad for their health." The research has shown that patients use an average amount of 0.7 grammes of cannabis per day, divided over multiple portions, for about 250 days.

The total number of registered patients in the Netherlands who use or have used medicinal cannabis is a little over 5,000. “Based on the medication they use in addition to the cannabis, we can draw conclusions about the diseases these patients have”, states Arno Hazekamp. For instance, according to the study results, more than half of the patients (53%) use another form of pain medication in addition to the cannabis. "In practice, this concerns patients who suffer from neuropathic pain, or pain due to MS, cancer or aids. The medicinal cannabis relieves their pain, stimulates their appetite, reduces nausea and improves their sleep."

Stable

The results of the study have shown that the use has been stable for the last ten years. Hazekamp thinks this is because medicinal cannabis is currently mainly prescribed as a last resort. "Patients receive medicinal cannabis only if they have been chronically ill for a very long time and after all regular medicines have been tried, to no avail. This leaves a relatively small group of patients, some of who die or are admitted to hospital, and therefore fall outside the scope of our study. Furthermore, doctors are still weary of prescribing medicinal cannabis. After all, unknown is unloved. Many people still have that image of 'a hippy stoner' in the back of their minds, even if these patients use cannabis for medicinal purposes.

Although Heerdink and Hazekamp focused their study on the more than 5,000 registered patients, it is uncertain whether that represents the actual number of Dutch patients who use cannabis for medicinal purposes. "The actual number is probably higher", says Heerdink. "It is likely that some patients go to 'coffeeshops', or grow their own cannabis. But the cannabis obtained in this way is of a varying quality. The medicinal cannabis issued by dispensing chemists is much more reliable."

Legal nursery

Bedrocan BV is the company which grows and distributes medicinal cannabis and it is the only legal nursery in Europe. Although it is an independent company, it is obliged to hand over the entire harvest to the government, from where it is distributed to Dutch dispensing chemists, but also to universities for research, or to patients abroad. "Although the amount of prescribed cannabis has remained stable, the production of Bedrocan has increased dramatically", reveals Hazekamp. "Their annual production has been increasing by 30% to 40% in the past years. This is mainly due to growing export and an increase in scientific research."

Next level

The results of the study are steady. They show that after its introduction the medicinal use of cannabis almost immediately stabilised to about 1,000 registered users per year, and a total of a little over 5,000 users in the period 2003-2010. “The research has given us the opportunity to take it to the next level”, says Heerdink. Hazekamp adds: "We have looked at one side, and the data has shown how the cannabis is distributed and prescribed. Our goal now is to analyse the other side, that of the patient. For what purpose did the patient use medicinal cannabis, and how did they like it?"

Meer informatie

• Dr. Rob Heerdink, Farmaceutical Sciences, faculty of Science, E.R.Heerdink@uu.nl, +31 (0)6 20 28 36 16
• Dr. Arno Hazekamp, Leiden University, ahazekamp@rocketmail.com, +31 (0)6 28 55 36 09
• Other questions: Tom de Kievith, press officer faculty of Science, t.dekievith@uu.nl, +31 (0)6 13 66 14 38.
• The article ‘The prevalence and incidence of medicinal cannabis on prescription in The Netherlands’ appeared online on the website of the European Journal of Clinical Pharmacology on April 17th.